An optical head device that is used for recording or reproducing information into or from an optical recording disk such as a CD or a DVD is provided with a wire suspension type of objective lens drive device has been known in the art. The wire suspension type of objective lens drive device includes an objective lens, a lens holder which holds the objective lens, a fixed side member which supports the lens holder with a plurality of wires in a movable manner, and a drive mechanism for driving the lens holder at least in a focusing direction and in a tracking direction.
The objective lens drive device used for this type of optical head device is a two-axes driven objective lens drive device has been known in the art. The two axes driven objective lens drive device has a drive mechanism for driving the lens holder in the focusing direction and the tracking direction is constructed by means of a pair of drive magnets having a magnetized opposing face and a focusing drive coil and a tracking drive coil opposedly disposed to the magnetized opposing face of the drive magnet. The drive magnet is provided with different magnetic poles whose boundary portions are formed in a U-shape. Each of the focusing drive coil and the tracking drive coil is disposed so as to extend over both the different magnetic poles across the boundary portion. (For example, see Japanese Patent Laid-Open No. 2003-45720). In the conventional objective lens drive device described above, the focusing drive coil and the tracking drive coil are formed on a printed coil circuit board.
However, the conventional objective lens drive device described above is not provided with a tilt drive mechanism. In other words, a tilt drive mechanism is not applied to the objective lens drive device. The conventional objective lens drive device is instead provided with the drive magnet having the magnetized opposing face in which the different magnetic poles are polarized and magnetized with the boundary portion in the U-shape.
On the other hand, in the industry, high-speed recording and reproduction has been required in the optical head device. In order to cope with the demand for high speed recording and reproduction, the objective lens drive device is required to be constructed such that a servo frequency for driving the objective lens in the focusing, tracking or tilt direction to control the position of the objective lens is increased to execute positional control of the objective lens at a higher frequency in the respective directions.
In the case that the servo frequency is increased at a higher value, resonance may occur in the objective lens drive device when the servo frequency approaches a high-order resonance frequency in the objective lens drive device. Therefore, when the high-order resonance frequency is low, it is difficult to control the objective lens at a high speed in the focusing direction, the tracking direction or in the tilt direction. Accordingly, in order to cope with a high-speed operation, the high-order resonance frequency is required to be higher.